The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
A typical multi-speed automatic transmission uses a combination of torque transmitting devices, such as clutches, dog clutches/synchronizers, or brakes, to achieve a plurality of forward and reverse gear or speed ratios as well as a Neutral and a Park. Selection of speed ratios is typically accomplished by a microprocessor transmission control module that employs various vehicle parameters, for example vehicle speed, and various driver input signals, for example accelerator pedal position, to select the appropriate speed ratios. The transmission then engages a combination of the toque transmitting devices to provide the desired speed ratios.
In order to engage the torque transmitting devices, a typical automatic transmission includes a hydraulic clutch control system that employs a hydraulic fluid to selectively actuate the torque transmitting devices. However, the conventional hydraulic clutch control system only provides single control gain and therefore the control resolution is limited (i.e. the conventional hydraulic clutch control system can only fully engage or disengage the torque transmitting device). However, in modern automatic transmissions it is desirable to have a hydraulic control system which can provide multiple control gains to control the torque capacity of torque transmitting devices. Accordingly, there is room in the art for a control system operable to provide multiple control gains using regulated pressurized hydraulic fluid to a torque transmitting device.